1. Field of the invention
The present invention relates to a hydraulic active suspension system for a vehicle such as an automobile or the like, and, more particularly, relates to a hydraulic active suspension system which is adapted to control the attitude of a vehicle body in response to its lateral acceleration.
2. Prior art
As described, for example, in Japanese Patent Laying Open Publications, Nos. Showa 62-295714 (1987) and Showa 63-242707 (1988), one of active suspension systems for a vehicle such as an automobile or the like, a hydraulic active suspension system has already been known which comprises a plurality of hydraulic actuators each being provided corresponding to a vehicle wheel and adapted to increase and decrease the vehicle height in response to the pressure within its working fluid chamber, a means for controlling the pressures within the working fluid chambers, a means for detecting the lateral acceleration of the vehicle body, and a control means for controlling the pressure control means based upon the lateral acceleration detected by the lateral acceleration detecting means so that the attitude change of the vehicle body may be suppressed or reduced which occurs in such a period when the vehicle turns.
In such conventional hydraulic active suspension systems as mentioned above, however, when a vehicle runs on a rough road or runs with the tires wearing chains or a door is opened and closed relatively violently, the lateral acceleration detecting means sometimes detects false lateral acceleration, causing an improper control to be effected based upon the falsely detected acceleration on the pressures within the working fluid chambers which are not to be changed and resulting in the unpleasent roll of the vehicle body.